Method and devices for running technology specific push-button configuration sessions

ABSTRACT

Overlapping Push Button Configuration (PBC) sessions are prevented without any deadlocks of technology specific PBC methods by controlling the run of technology specific PBC sessions within a heterogeneous network of network node devices interconnected via at least one I interface and/or over multiple hops and authenticated for the network, by enabling a two-level PBC within the heterogeneous network based on a network node device of the network node devices being authenticated for the network as registrar, which is especially selectable or determined. Level- 1  of the two-level PBC performed at the abstraction layer of the heterogeneous network accomplishes the detection of the wish for PBC, prevention of overlapping PBC sessions independent of underlying communication technology, coordination of technology-specific PBC runs, whereas in level- 2  of the two-level PBC performed within a technology-specific communication technology a technology-specific PBC is used, which is triggered by the level- 1.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage of International ApplicationNo. PCT/EP2013/057603, filed Apr. 11, 2013 and claims the benefitthereof. The International application claims the benefits of EuropeanApplication No. 12163681 filed on Apr. 12, 2012, both applications areincorporated by reference herein in their entirety.

BACKGROUND

Described below are a method for controlling the run of technologyspecific Push Button Configuration sessions within a heterogeneousnetwork with multiple communication network technologies, a registrarnetwork node device for controlling the run of technology specific PushButton Configuration sessions within a heterogeneous network withmultiple communication network technologies, a computer readable storagemedia executable by a processor for controlling the run of technologyspecific Push Button Configuration sessions within a heterogeneousnetwork with multiple communication network technologies and aheterogeneous network for controlling the run of technology specificPush Button Configuration sessions.

The current data-centric use of networks (Internet access, mediastreaming) is increasingly extended towards home control functionality(home automation for climate control, lighting, burglar alarm, homeenergy network). Such home networks use according to FIG. 1 for instancevarious communication network technologies like Ethernet (IEEE 802.3),WLAN/WiFi (IEEE 802.11), and Power Line Communication (PLC; IEEE 1901).For this reason they are heterogeneous. The standard IEEE P1905.1, whichaccording to D02 Draft Standard for Convergent Digital Home Network(CDHN) for Heterogeneous Technologies from Dec. 14, 2011 (described inIEEE P1905.1/D02 Draft Standard for Convergent Digital Home Network forHeterogeneous Technologies, IEEE P1905.1 document 1905_1-11-0101-02) iscurrently under development, defines a home network standard supportingdifferent network technologies by a specified “IEEE P1905.1”-AbstractionLayer.

FIG. 2 shows the design of the abstraction layer based on theISO/OSI-Reference Model with a management and data plane. Theabstraction layer is embedded in an IEEE P1905.1-Architecture above aMedia Access Control (MAC)-layer and a Physical layer as part of a“Network Node Device” NND within the heterogeneous network. Thus, thenetwork node device NND uses the cited technologies like Ethernet (IEEE802.3), WLAN/WiFi (IEEE 802.11), and Power Line Communication (PLC; IEEE1901) and additionally a technology according to the specification ofthe Multimedia over Coax Alliance (MoCA) via corresponding interfacesaccording to FIG. 2. It is not compulsory or mandatory for a typicalnetwork node device to support all cited communication technologies. Itis possible that the network node device NND supports only one or two ofthe cited technologies or completely other network technologies. Thusthe network node device NND supports at least one network technology.

At least one goal of the IEEE P1905.1 standardization activities is thesecurity mechanism during a setup or registration of a new device,called an “enrollee”, which wants to join the heterogeneous network. Thesecurity mechanism is needed to protect the home network from externalattacks. Such security mechanisms have to be configured with a securitycredential (password, passphrase, cryptographic key) that is burdensometo set-up manually.

The specific problem of using a Push-Button Configuration (PBC) in an“IEEE P1905.1”-network comes from the fact that multiple devices(belonging even to different technologies) are activated to accept a newdevice. So in the current version of the standard, more than one devicecould register with the “IEEE P1905.1”-network after a single buttonpress. An attacker node may therefore register undetected when anauthorized registration of a new device takes place. Further, even in ascenario where there is no attacker node, if multiple existing nodes ofthe home network (for e.g. access points) activate their technologyspecific PBC mode simultaneously it may lead to failure of the newnode's attempts to join the network. This is specifically the case whenthe access points (or the nodes involved in registering the new node inthe network via the technology specific Push Button Configuration) areIEEE 802.11 (WLAN) access points supporting as a Push-ButtonConfiguration in the WLAN environment a Wi-Fi Protected Setup (WPS).Taking this into account a technology specific Push Button Configurationis a Push Button Configuration, which is used specifically for each ofthe communication network technologies within the heterogeneous network.

Currently a push button method is provided in heterogeneous convergentdigital home networks in order to allow the end-user to easily setup thesecurity credentials and permit new network devices to join theconvergent digital home network. An example for this is the mechanismprovided in the IEEE P1905.1 draft standard under development. Hereusing the P1905.1 push button mechanism, technology specific Push ButtonConfigurations (PBC) are activated on authenticated devices in the homenetwork. This enables the new joining device to carry out a technologyspecific Push Button Configuration itself with a suitable device (basedon range, connectivity, and media type) to get security credentials tojoin the home network.

One of the basic problems with this is, that multiple technologyspecific Push Button Configurations (PBC) triggered by the same pushbutton event may actually fail because they recognize each other as aconflicting PBC run. This is especially the case in Wi-Fi ProtectedSetup (WPS) with “Wi-Fi”-devices.

The mechanisms provided however are limited, for example, they do notwork for the case of home networks where multiple registrars are present[multiple registrars are possible, see page 11 of the “Wi-Fi ProtectedSetup (WPS)” Specification defined by the Wi-Fi Alliance Version 1.0,September 2006, which is the de-facto standard for WLAN security setup(see en.wikipedia.org/wiki/Wi-Fi_Protected_Setup andwww.wi-fi.org/wifi-protected-setup).

Furthermore in the IEEE P1905.1 solution the technology specificPush-Button Configuration is started only by the registrar, whichimplies that for the case where the new device is not within range ofthe registrar, but within the range of another “Wi-Fi”-access point thePush-Button Configuration attempt fails.

Additionally, the registrar is a logical entity and can be separatedfrom the access points. In this case the registrar itself might not havethe capability to start a “Wi-Fi” specific Push Button Configuration atall. This will prevent any nodes from joining the network using the“Wi-Fi” technology specific PBC.

Convergent Digital Home Networks (CDHNs) are home networks wheredifferent heterogeneous communication technologies are converged in asingle home network. This is done by introducing an abstraction layerabove the different communication technologies. The goal is a commonuser view and user experience independent of the underlyingcommunication technology.

Such a Convergent Digital Home Network is being defined, for instance,in the IEEE P1905.1 working group. The IEEE P1905.1 standard which iscurrently being defined specifies an abstraction layer, which convergesIEEE 802.3, IEEE 802.11, IEEE 1901 (PLC), and Multimedia over CoaxAlliance (MoCA®) and is extensible to other communication technologies.

Push Button Configuration is an accepted technique for user-friendlysecurity setup in home networks. In a Convergent Digital Home Network,the push button configuration has to be agnostic to the underlyingcommunication technologies.

The idea is that the user presses a push button on any of the networkdevices (the network Push Button Event (NW-PBE)) and on the new device,the enrollee (the enrollee Push Button Event (E-PBE)). This will startthe push button configuration, even in the case where the network nodewith the NW-PBE and the enrollee have no communication technology incommon, that is, they communicate through intermediate network nodes ofthe Convergent Digital Home Network. Changes to the technology-specificPBC method are considered to be too expensive and are not backwardcompatible.

Several communication technologies provide a technology-specific PushButton Configuration method (ts-PBC method). Such a method can betriggered by the abstraction layer of the Convergent Digital HomeNetwork, but the ts-PBC is solely controlled by the rules of thespecific communication technology. That is, the Convergent Digital HomeNetwork can not influence the ts-PBC run except for starting it.

The problem of “overlapping PBC sessions” is, that more than one device(enrollee) wants to join the network for a single push button event. Itcan be assumed that one of the devices is an attacker. The problem ofoverlapping PBC sessions is according to FIG. 3 more severe inConvergent Digital Home Networks due to the potential multi-hop natureand the different communication technologies:

-   -   The overlapping PBC sessions might happen with different        technologies, so that technology-specific mechanisms for the        detection of overlapping PBC sessions will not work.    -   The geographic distance between the overlapping PBC sessions can        be larger compared to ts-PBC sessions due to the multi-hop        capability of the Convergent Digital Home Network. In a specific        technology, the Push Button Configuration is usually focused on        a single network device such as a Wi-Fi Access Point. In a        Convergent Digital Home Network, the Push Button Configuration        can happen at any network node with a ts-PBC method.

The “deadlock of technology specific PBC sessions” is a new problem thatoccurs in Convergent Digital Home Networks. If the Convergent DigitalHome Network starts multiple ts-PBC sessions of the same communicationtechnology due to the propagation of the NW-PBE to all ConvergentDigital Home Network nodes, each ts-PBC session will detect each otheras an overlapping session and will cancel the Push Button Configurationruns, so that no Push Button Configuration will happen for thiscommunication technology at all.

Particularly, this is a problem of Wi-Fi Protected Setup, the PBC methodfor IEEE 802.11/Wi-Fi (cf. FIG. 3).

The current version of the draft IEEE P1905.1 specification does notdefine a mechanism for preventing or detecting overlapping sessions inthe increased scope of this problem in Convergent Digital Home Networks.

IEEE P1905.1 submission 11/0087r1 (see [Parag Mogre, Michael Bahr:Security Improvements for P1905.1, IEEE P1905.1 document1905_1-11-0087-01) defines a similar method that detects and preventsoverlapping sessions in a Convergent Digital Home Network, but itrequires some interaction with the technology-specific PBC method. TheCDHN node detects an enrollee solely based on the receivedtechnology-specific PBC messages sent by the enrollee; and in case ofoverlapping PBC sessions a PBC Abort message stops ongoing ts-PBC runs.

Furthermore, such a functionality as a CDHN registrar is not known andsome parts of the description are rather high level.

IEEE P1905.1 submission 12/007r1 (see Parag Mogre, Michael Bahr: PushButton, IEEE P1905.1 document 1905_1-12-0007-01) describes a schemerudimentarily that at least detects overlapping PBC sessions, but cannotprevent them. The CDHN nodes are informed about successful Push ButtonConfigurations.

The current version of the draft IEEE P1905.1 specification does definea method targeted at the problem of deadlock of ts-PBC sessions for thecase of Wi-Fi Protected Setup. Only the Access Point (AP) where theNW-PBE occurred (push button pressed) or the Wi-Fi registrar can startthe WPS push button method. The short-coming of this method is that anenrollee will never be able to connect to the network if it is only inrange of an access point that will not be allowed to enable the WPS PushButton Configuration.

IEEE P1905.1 submission 12/007r1 describes an alternative scheme for theproblem of deadlock of Wi-Fi Protected Setup PBC sessions. Here, onlythe AP where the NW-PBE occurred (push button pressed) is activated orall access points are activated with a random delay. This means, thatall access points start their WPS PBC at different times therebyreducing the chance of deadlock due to technology-specific overlappingPBC sessions while connecting the enrollee at any access point of theConvergent Digital Home Network.

The most well-know technology-specific Push Button Configuration methodis as indicated above the Wi-Fi Protected Setup (WPS) described in Wi-FiProtected Setup Specification, Version 1.0, September 2006.

The method and network node device described below for controlling therun of technology specific Push Button Configuration sessions within aheterogeneous network with multiple communication network technologiesas well as a heterogeneous network with multiple communication networktechnologies, is capable of achieving a reliable prevention ofoverlapping PBC sessions without any deadlocks of technology specificPBC methods.

SUMMARY

The enhanced mechanism described below controls the run of technologyspecific Push Button Configuration sessions within a heterogeneousnetwork with multiple communication network technologies and a pluralityof network node devices interconnected to each other via at least oneinterface and/or over multiple hops and authenticated or unauthenticatedfor the network, by enabling a two-level Push Button Configurationwithin the heterogeneous network, especially within a Convergent DigitalHome Network (CDHN) according to the IEEE P1905.1 standard specific,based on a network node device of the network node devices beingauthenticated for the network as registrar, which is especiallyselectable or determined.

The level-1 of the two-level Push Button Configuration performed at theabstraction layer (cf. FIG. 2) of the heterogeneous network respectivelythe Convergent Digital Home Network (CDHN) accomplishes the detection ofthe wish for Push Button Configuration, prevention of overlapping PBCsessions independent of underlying communication technologies,coordination of technology-specific PBC runs, especially the selectionof a network node for the technology specific Push Button Configuration(ts-PBC) and the triggering of the technology specific Push ButtonConfiguration, whereas in the level-2 of the two-level Push ButtonConfiguration performed within a technology-specific communicationtechnology a technology-specific Push Button Configuration is used,which is triggered by the level-1 of the two-level Push ButtonConfiguration.

Thereby especially the registrar network node device, called as CDHNregistrar, should not be confused with a registrar of atechnology-specific PBC method such as a WPS registrar (Wi-Fi ProtectedSetup). The method assumes a clear distinction between the functionalityof the CDHN registrar and the functionality of a registrar for atechnology specific Push Button Configuration method. However, realimplementations may combine both functionalities.

It is advantageous to provide a method for reusing push buttonconfiguration methods specific to a communication technology in aconvergent digital home network, such as for example IEEE 1905.1networks.

It is advantageous to provide ease of use to the user of the homenetwork and the same level of user experience of user convenience aswell-known technology-specific push button configuration protocols suchas the Wi-Fi Protected Setup.

The user can press the push buttons in any order, and the push button ofany device already part of the network, independent of the availablecommunication technologies at this device, will allow the new device tobe authenticated for communication in the Convergent Digital HomeNetwork with the corresponding PBC method.

It is advantageous to detect and prevent overlapping PBC sessions. Atthe CDHN level, this is the push button configuration of more than oneenrollee for one push button event. On the other hand, the method allowshaving multiple PBC runs for multiple interface of the very sameenrollee for a single PBE.

It is advantageous to avoid deadlock of technology-specific PBC runs. Atthe CDHN level, the CDHN registrar will collect and analyze candidateCDHN nodes for ts-PBC runs and does an election of the CDHN nodes thatwill start their ts-PBC method. This avoids deadlock of ts-PBC runs.Alternative selection criteria allow different degrees of granularityand smartness for the election of CDHN nodes.

It is advantageous that there is a single CDHN registrar, whichcoordinates the prevention of overlapping PBC sessions and potentialdeadlocks of ts-PBC runs. Simple methods for assigning the CDHNregistrar functionality to a node of the Convergent Digital Home Networkare provided.

It is advantageous to describe messages and the flow of these messagesfor exchanging information related to the Convergent Digital HomeNetwork's Push Button Configuration (CDHN PBC) on the level-1 of thetwo-level Push Button Configuration.

The CDHN PBC is divided in two levels. The level-1 is located at theCDHN layer and controls the PBC functionality with respect to theConvergent Digital Home Network providing most of the positive CDHN userexperience with respect to Push Button Configuration. The actual PushButton Configuration for a communication technology is performed withunchanged existing PBC methods of the communication technologies.

No changes to the ts-PBC methods are required. This avoids high costsfor changes and ensures backward compatibility of home network devices.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages will become more apparent andmore readily appreciated from the following description of the exemplaryembodiments, taken in conjunction with Tables 1 to 4 and theaccompanying drawings of which:

FIG. 1 is a block diagram of various communication network technologies,

FIG. 2 is a block diagram of the design of the abstraction layer basedon the ISO/OSI-Reference Model with a management and data plane,

FIG. 3 is a block diagram illustrating overlapping PBC sessions,

FIG. 4 is a block diagram of a Convergent Digital Home Network (CDHN)with different underlying communication technologies,

FIG. 5 a sequence diagram with the message flow for a two-levelConvergent Digital Home Network (CDHN) Push Button Configuration method,

FIG. 6 is a block diagram based on FIG. 4 of a modified ConvergentDigital Home Network (CDHN) for detecting and preventing overlapping PBCsessions and preventing deadlock of technology-specific Push ButtonConfigurations,

FIG. 7 a sequence diagram for detecting and preventing overlapping PBCsessions,

FIG. 8 a sequence diagram for preventing a deadlock between PBC sessionsof the same technology,

FIG. 9 is a block diagram illustrating the structure of a network nodedevice for controlling the run of technology specific Push ButtonConfiguration sessions within a heterogeneous network with multiplecommunication network technologies based on the abstraction layerembedded in the IEEE P1905.1-Architecture above the Media Access Control(MAC)-layer and the Physical layer according to FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings, whereinlike reference numerals refer to like elements throughout.

FIG. 4 shows an example network topology of a heterogeneous network suchas a Convergent Digital Home Network (CDHN). The network node devices D1. . . D6 of the Convergent Digital Home Network are connected with eachother through possibly heterogeneous communication technologies. Thenetwork node devices of the Convergent Digital Home Network are alsocalled CDHN nodes. Communication between devices of the network can beover multiple hops. The Convergent Digital Home Network of FIG. 4contains besides the network node devices respectively CDHN nodes D1 . .. D6 more network node devices than the cited ones and those devices areintermediate nodes on the communication between CDHN nodes D1 . . . D6.With respect to FIG. 2 the devices have different underlyingcommunication technologies MAC “A”, MAC “B”, MAC “C”, and MAC “E”. TheMAC “A” might be WLAN/WiFi (IEEE 802.11), the MAC “C” might be the PowerLine Communication (PLC; IEEE 1901), the MAC “E” might be Ethernet (IEEE802.3), and the MAC “B” might be some other communication technology,e.g. Multimedia over Coax Alliance (MoCA).

The IEEE 1905.1 specification is an example for a Convergent DigitalHome Network (CDHN). An embodiment is described below with general CDHNterminology. A similar embodiment is also applicable for IEEE 1905.1networks and similar networks.

According to the embodiment described below, the Convergent Digital HomeNetwork contains a network node device, namely the registrar networknode device or CDHN registrar. The CDHN registrar is a logical componentwith a special functionality that can be located at any network nodedevice of the Convergent Digital Home Network.

According to FIG. 4 the registrar functionality is assigned to thenetwork node device D6. The assignment to a network node device can bedone by selection/determination of a single CDHN registrar based ondifferent methods, amongst them are:

-   -   M1: Manual configuration (mechanical configuration through e.g.        switches, by software e.g. a network management tool)    -   M2: The first node of the Convergent Digital Home Network        becomes the CDHN registrar.    -   M3: The gateway of the home network is the CDHN registrar.    -   M4: The CDHN node in the network where the Push Button has been        pressed [where network Push Button Event (NW-PBE) happened]        becomes the CDHN registrar for this CDHN Push Button        Configuration.    -   M5: Selection algorithm that leads to a choice of the CDHN        registrar that is consistent between all nodes of the Convergent        Digital Home Network.

The information which CDHN device is the CDHN registrar needs to be madeavailable to all nodes in the Convergent Digital Home Network.

-   -   For methods M1, M2, and M3 for selecting a single CDHN        registrar, this can be done for instance by announcing the CDHN        Registrar with corresponding announcement messages in the        Convergent Digital Home Network. These CDHN registrar        announcement messages can be, for instance, broadcast to all        nodes in the Convergent Digital Home Network by relayed        multicast.    -   For method M4 for selecting a single CDHN registrar, this        information corresponds to the originator of the PBE        Notification message (described in the following) and can be        taken from a notification message notifying about the Push        Button Event, e.g. the network Push Button Event NW-PBE, the        so-called PBENotification message.    -   For method M5 for selecting a single CDHN registrar, this        information might be provided by the used selection algorithm or        the CDHN registrar is announced as for methods M1, M2, and M3.

Once again the CDHN registrar should not be confused with a registrar ofa technology-specific Push Button Configuration method such as a WPSregistrar. The method assumes a clear distinction between thefunctionality of the CDHN registrar and the functionality of a registrarfor a technology-specific Push Button Configuration method. However,real implementations may combine both functionalities.

The level-1 of the two-level Push Button Configuration performed at theabstraction layer (cf. FIG. 2) of the heterogeneous network respectivelythe Convergent Digital Home Network (CDHN) accomplishes the detection ofthe wish for Push Button Configuration, prevention of overlapping PBCsessions independent of underlying communication technology,coordination of technology-specific PBC runs, especially the selectionof a network node for the technology specific Push Button Configuration(ts-PBC) and the triggering of the technology specific Push ButtonConfiguration, whereas in the level-2 of the two-level Push ButtonConfiguration performed within a technology-specific communicationtechnology a technology-specific Push Button Configuration is used,which is triggered by the level-1 of the two-level Push ButtonConfiguration.

Different actions are performed on the enrollee and the network nodesfor the level-2 of the Convergent Digital Home Network Push ButtonConfiguration method. Enrollee and CDHN nodes can be distinguished, forinstance, based on their authentication and association state. Someexamples are shown in Table 1.

TABLE 1 Examples for distinction between enrollee and CDHN node EnrolleeCDHN node no valid network ID valid network ID not associated to CDHNassociated to CDHN unauthenticated network has authenticated interfaces(no authenticated network interfaces network interface) no successfulpush button successful push button configuration done configuration done

In order to authenticate a new CDHN node, the enrollee, with anotherCDHN node that is already part of a Convergent Digital Home Network, apush button has to be pressed at the enrollee and at any CDHN node ofthe network. The push button can be a real button, a software button, ora virtual button (by, e.g., a software instruction triggering a PushButton Event). The order for pressing the push buttons is arbitrary(enrollee first or enrollee second).

Pressing the push button at the enrollee creates a Push Button Event(PBE), it is called the enrollee Push Button Event (E-PBE). Pressing thepush button at the network node device creates a Push Button Event(PBE), it is called the network Push Button Event (NW-PBE).

FIG. 5 shows the flow of messages in a CDHN network according to anembodiment in a sequence diagram. The messages are explained further onin the text, including when to generate the messages and what to do uponthe receipt of a message.

Upon pressing a push button on a new device ND as enrollee beingunauthenticated for the heterogeneous network an enrollee Push ButtonEvent E-PBE is released for what reason the enrollee start itstechnology-specific Push Button Configuration (ts-PBC) and announce itswish to perform a PBC run at the CDHN layer (level-1 of the two-levelPush Button Configuration) by sending, especially periodically,PBCActivated messages.

Upon pressing a push button on one network node device of the networknode devices D1 . . . D4 being authenticated for the network, which ise.g. according to FIG. 5 the first network node device D1, a networkPush Button Event NW-PBE is released for what reason the first networknode device D1 distributes the Push Button Event NW-PBE to all otherauthenticated CDHN nodes D2, D3, D4 of the network node devices D1 . . .D4 in the network—of which according to FIG. 5 the network node deviceD2 is the CDHN registrar and the network node devices D3, D4 areadjacent to the enrollee—the new network node device ND—by sending andrelaying a PBENotification message.

The network node devices D1 . . . D4 are listening for PBCActivatedmessages during a CDHN Walk Time. The information of the PBCActivatedmessage and additional information is forwarded to the CDHN registrar D2in PBCRequest messages. The CDHN registrar D2 selects the CDHN node D3and the corresponding interfaces that are allowed to perform atechnology-specific Push Button Configuration run based on theinformation of the collected PBCRequest messages.

If the CDHN registrar detects overlapping Push Button Configurationsessions, no CDHN node is selected. If the CDHN registrar detects apossible deadlock of technology-specific Push Button Configurations,only one candidate CDHN node or interface is selected.

A PBCStart message is sent to the selected CDHN node D3 by the CDHNregistrar D2. On receipt of a PBCStart message, the CDHN node D3 startsits technology-specific Push Button Configuration on the specifiedinterface.

Level-1 Actions of the Two-level Push Button Configuration on anEnrollee Push Button Event E-PBE at the Third Network Node DeviceRespectively the Enrollee ND (Level-1 Actions on E-PBE):

On an enrollee Push Button Event E-PBE, the enrollee ND takes thefollowing actions at the CDHN layer (level-1 of the two-level PushButton Configuration):

-   -   The enrollee goes into a state “CDHN_PBC_enabled”, where level-1        actions of the CDHN Push Button Configuration method are        allowed. This state has a maximum duration of a CDHN walk time,        for instance, 120 seconds.    -    Note: The state CDHN_PBC_enabled is a logical concept in this        description and can be described and implemented in many        different ways, for example, as state variable, as Boolean        variable, as timer, as active timer, as “during CDHN walk time”,        etc.    -   The enrollee starts the technology-specific Push Button        Configuration methods (ts-PBC methods), if available, on each of        its unauthenticated (CDHN) interfaces.    -   If the enrollee is in state CDHN_PBC_enabled, it sends messages        “PBCActivated” to all its unauthenticated (CDHN) interfaces        especially periodically. The periodicity has to be chosen in        such a way that fast discovery of the enrollee within the CDHN        walk time is ensured. The interval for PBCActivated messages may        be, for instance, 1 second. The periodicity might be different        at the different interfaces and might be determined by specific        mechanisms of the underlying communication technology (e.g.        beacon intervals).    -   The PBCActivated message can be realized in different ways, for        example:    -   As a specific PBCActivated message.    -   As one or more additional data structures, so called Type Length        Value (TLV) encodings, included in already existing message        specifications, e.g. Neighbor Discovery messages.

The PBCActivated message or its representation includes the followingparameters amongst other possible parameters:

-   -   Some ID or type value that indicates that it is a PBCActivated        message or equivalent (Parameter A1).    -   The CDHN MAC Address of the enrollee. This is required to        recognize duplicates of the PBCActivated message of the same        enrollee (Parameter A2).    -   A Push Button Event ID (PBE ID). This is a parameter that helps        to distinguish multiple push button events of the same enrollee        (Parameter A3).    -   The MAC Address of the interface, through which the PBCActivated        message has been sent. This is a parameter to distinguish        multiple interfaces, especially of the same communication        technology (Parameter A4).    -   Media information about the communication technology of the        interface, through which the PBCActivated message has been sent.        This is a parameter that can help the CDHN registrar to make a        better selection of the CDHN node for the technology-specific        PBC run. The media information is less useful for wired        communication technologies than for wireless communication        technologies. Moreover, the media information can be used to        distinguish PBCActivated messages of the same enrollee that are        sent over different communication technologies (Parameter A5).        Level-1 Actions of the Two-Level Push Button Configuration on a        Network Push Button Event NW-PBE at the First Network Node        Device Respectively the CDHN Node D1 (Level-1 Actions on        NW-PBE):

On a network Push Button Event NW-PBE the CDHN node D1 takes thefollowing actions at the CDHN layer (level-1 of the two-level PushButton Configuration):

-   -   The CDHN node goes into a state “CDHN_PBC_enabled”, where        level-1 actions of the CDHN Push Button Configuration method are        allowed. This state has a maximum duration of CDHN walk time,        for instance, 120 seconds.    -    Note: The state CDHN_PBC_enabled is a logical concept in this        description and can be described and implemented in many        different ways, for example, as state variable, as Boolean        variable, as timer, as active timer, as “during CDHN walk time”,        etc.    -   The CDHN node sends a Push Button Event Notification message        (PBE Notification message) to all other nodes of the CDHN. The        PBENotification message may be sent by broadcast or relayed        multicast.

The PBENotification message or its representation includes the followingparameters:

-   -   Some ID or type value that indicates that it is a        PBENotification message or equivalent.    -   The CDHN MAC Address of the originator of the PBENotification        message, that is, the CDHN node with the NW-PBE. This is a        parameter. can be used to recognize multiple NW-PBEs.    -   A Push Button Event ID (PBE ID). This is a parameter that helps        to distinguish multiple push button events of the same CDHN node        or within the CDHN.    -   Both, CDHN MAC Address and/or PBE ID can be used to detect        duplicate PBENotification messages during the propagation within        the Convergent Digital Home Network.

On receipt of a PBENotification message a CDHN node takes the followingactions at the CDHN layer (level-1 of the two-level Push ButtonConfiguration):

-   -   The CDHN node may perform duplicate detection for the received        PBENotification message and discards any duplicates of an        already received PBENotification.    -   The CDHN node goes into a state “CDHN_PBC_enabled”, where        level-1 actions of the CDHN Push Button Configuration method are        allowed. This state has a maximum duration of CDHN walk time,        for instance, 120 seconds.    -    Note: The state CDHN_PBC_enabled is a logical concept in this        description and can be described and implemented in many        different ways, for example, as state variable, as Boolean        variable, as timer, as active timer, as “during CDHN walk time”,        etc.    -   The CDHN node propagates the PBENotification method according to        the propagation rules (broadcast, relayed multicast, duplicate        detection) to its neighbor CDHN nodes.

Now, all nodes of the Convergent Digital Home Network are in stateCDHN_PBC_enabled and wait for the receipt of PBCActivated messages sentby the enrollee.

If a CDHN node is in state CDHN_PBC_enabled and receives a PBCActivatedmessage it does the following:

-   -   The CDHN node may perform duplicate detection for the received        PBCActivated message and discards any duplicates of an already        received PBCActivated message.    -   The CDHN node sends the content of the PBCActivated message to        the CDHN registrar, e.g., by (relayed) unicast. This can be        realized in different ways:    -   Forwarding the PBCActivated message to the CDHN registrar.    -   As a specific message, for instance, a Push Button Configuration        Request (PBCRequest) message.    -   As one or more additional data structures, so called Type Length        Value (TLV) encodings, included in already existing message        specifications that are sent to the CDHN registrar.

The forwarded PBCActivated message, the PBCRequest message, or theirrepresentations may include the following additional parameters:

-   -   Some ID or type value that indicates that it is a PBCRequest        message or equivalent (Parameter A6).    -   Media information about the communication technology of the        interface through which the PBCActivated message has been        received. This is a parameter that can help the CDHN registrar        to make a better selection of the CDHN node for the        technology-specific PBC run. The media information is less        useful for wired communication technologies than for wireless        communication technologies. However, the media information can        be used to distinguish PBCActivated messages of the same        enrollee that are sent over different communication technologies        (Parameter A7).    -   Some additional information about the link quality. This is a        parameter with information especially useful for wireless        interfaces. The CDHN registrar can base the election of the        network node for the PBC run on the best link quality (Parameter        A8).    -   The CDHN MAC Address of the recipient of the PBCActivated        message or the originator of the PBCRequest message. This is        required in order to know the CDHN node that is a potential        candidate for being selected for performing a        technology-specific PBC run, i.e. being the recipient of a        PBCStart message (Parameter A9).    -   A Push Button Event ID (PBE ID). This is a parameter that helps        to distinguish multiple push button events in the network. It        also helps to link PBENotification messages and        PBCActivated/PBCRequest messages to a specific push button event        (Parameter A10).    -   The MAC Address of the interface through which the PBCActivated        message has been received. This is a parameter to distinguish        multiple interfaces at the same CDHN node, especially of the        same communication technology (Parameter A11).

In the following, the term PBCRequest message is used for the abovedescribed forwarded and extended PBCActivated message, the PBCRequestmessage containing the content of the received PBCActivated message, orthe corresponding representation.

If a CDHN registrar is in state CDHN_PBC_enabled and receives aPBCRequest message it does the following:

-   -   If it is the first PBCRequest message it receives during this        CDHN walk time or period of state CDHN_PBC_enabled, it saves the        received PBCRequest message and waits some time        T_wait_PBCRequest in order to wait for possible further        PBCRequest messages.    -   T_wait_PBCRequest is smaller than CDHN walk time and may be, for        example, 10, 12, or 20 seconds. T_wait_PBCRequest should cover a        time period that allows all CDHN nodes to receive PBCActivated        message from the enrollee (if there is a possible link between        the enrollee and the CDHN node) plus the necessary time for the        generation and the communication of the PBCRequest from the CDHN        node to the CDHN registrar.    -   After T_wait_PBCRequest is over, the CDHN registrar performs the        methods for detecting and preventing overlapping PBC sessions        and for electing the CDHN node(s) for running the ts-PBC.        Detection and Prevention of Overlapping PBC Sessions:

The CDHN registrar counts how many different enrollee CDHN MAC addressesare contained in all PBCRequest messages received duringT_wait_PBCRequest.

If all received PBCRequest message contain the same Parameter A2, theenrollee CDHN MAC address, (count is 1), only a single enrollee wants tojoin the network and the registrar can proceed to the election of an(already authenticated) CDHN node for the ts-PBC run.

If there are different Parameter A2, the enrollee CDHN MAC address, inall received PBCRequest messages (count is greater than 1), there aremultiple enrollees wanting to join the network. This constitutesoverlapping PBC sessions in a Convergent Digital Home Network. Theoverlapping sessions are prevented by not election any CDHN node for thets-PBC run, that is, the enrollees will not find a partner for theirtechnology-specific Push Button Configuration. In case of overlappingPBC session, the CDHN may issue an error indication or starts anyappropriate action for the case of overlapping PBC sessions.

However, it might happen due to unfortunate timing of the push buttonevent at the second (overlapping) enrollee, that the PBCRequest messagestriggered by the PBCActivated messages of this second (overlapping)enrollee arrive only after the CDHN registrar has already elected andinformed a CDHN node for the ts-PBC run and while the CDHN walk time isstill active, that is, the CDHN registrar is still in the stateCDHN_PBC_enabled for the same NW-PBE. In this case no CDHN node iselected for this enrollee, that is, the second (overlapping) enrolleewill not find a partner for its ts-PBC. Since it is not clear whetherthe first or the second enrollee is the one the user wishes toauthenticate, the Convergent Digital Home Network may issue an errorindication or starts any appropriate action for this case of overlappingPBC sessions.

In an extension, the chances for such a situation of overlapping PBCsessions (first enrollee already authenticated before second enrollee isdetected) can be decreased by increasing the duration ofT_wait_PBCRequest. Here, the CDHN registrar will listen longer forPBCRequest messages.

Election of CDHN Node(s) for Running the Technology-specific Push ButtonConfiguration (Ts-PBC):

A CDHN node for running the ts-PBC is only selected if there is exactlyone enrollee (CDHN device).

The CDHN registrar elects the CDHN node or nodes for running thetechnology-specific push button configuration based on the Parameter A4and Parameter A11 that are contained in all PBCRequest messages receivedduring T_wait_PBCRequest.

Each distinct Parameter A4, the MAC Address of the interface throughwhich the PBCActivated messages have been sent by the enrollee,corresponds to an interface of the enrollee for which a ts-PBC has to betriggered at one of the CDHN nodes.

The CDHN registrar determines how many different Parameter A11, the MACAddress of the interface through which the PBCActivated message has beenreceived at the originator of the PBCRequest message, are reported foreach distinct Parameter A4 in the received PBCRequest messages. In otherwords, the tuples <Parameter A4, Parameter A11> are analyzed or, withother words, all potential links between the enrollee and a CDHN node ofthe network are counted and analyzed.

If there is only one distinct Parameter A11 for a specific Parameter A4,then only one CDHN node is a potential PBC partner. The originator ofthe corresponding PBCRequest (Parameter A9) will be elected as CDHN nodefor the ts-PBC for this communication technology defined by theinterface (Parameter A11).

If there is more than one distinct Parameter A11 for a specificParameter A4, then more than one communication technology interfaces arepotential PBC partners for the very same interface of the enrollee. Thedifferent communication technology interfaces might be located at thesame CDHN node or at more than one CDHN nodes. It is very likely, that adeadlock of the ts-PBC will happen if all originators of thecorresponding PBC Requests (Parameter A9) will be elected as CDHN nodefor the ts-PBC for the communication technology defined by theinterfaces (Parameter A11). The CDHN registrar elects one CDHN node andone of its reported interfaces of the possible CDHN nodes and interfacesas CDHN node for the ts-PBC for this communication technology defined bythe interface (Parameter A11). The possible CDHN nodes and interfacesare reported in the received PBCRequest messages and determined in theanalysis of the tuples <Parameter A4, Parameter A11.

Alternative parameter choices for detecting multiple candidate CDHNnodes for a specific interface of the enrollee are amongst others:

-   -   CDHN MAC Address of the recipient of the PBCActivated message        (tuples <Parameter A4, Parameter A9>): The CDHN MAC Address        provides the capability to detect multiple candidate CDHN nodes        independent of their communication technologies that could        connect to the enrollee.    -   Media Information (tuples <Parameter A4, Parameter A5> or        <Parameter A4, Parameter A7>): The media information provides        the capability to detect multiple candidate CDHN nodes for the        same technology. Only one candidate CDHN node for a        communication technology is selected. Based on pre-knowledge        which communication technology will cause deadlock for ts-PBC        runs, only for those the selection of CDHN nodes has to be        restricted to a single elected CDHN node in an extension.    -   Any combination of Parameter A11, Parameter A9, Parameter A4, or        Parameter A5. The more information is available the more        fine-grained and smarter the election of CDHN nodes can be        performed.

The CDHN registrar sends a PBCStart message to all elected CDHN nodes.The PBCStart messages may be sent by (relayed) unicast.

The PBCStart message can be realized in different ways:

-   -   As a specific PBCStart message.    -   As one or more additional data structures, so called Type Length        Value (TLV) encodings, included in already existing message        specifications.

The PBCStart message or its representation includes the followingparameters among others:

-   -   Some ID or type value that indicates that it is a PBCStart        message or equivalent.    -   The CDHN MAC Address of the elected CDHN node. This CDHN node        has been an originator of a PBCRequest message. The value for        this parameter can be taken from Parameter A9 of the        corresponding PBCRequest message (CDHN MAC Address of the        recipient of the PBCActivated message or the originator of the        PBCRequest message). This is required as the destination of the        PBCStart message (Parameter A12).    -   The MAC Address of the interface at which the        technology-specific PBC run has to be started. This is a        parameter with a value that can be taken from Parameter A11 of        the corresponding PBCRequest message (MAC Address of the        interface through which the PBCActivated message has been        received). This parameter is necessary if the ts-PBC run has to        be started not at all interfaces but only at a specific        interface (Parameter A13).    -   A Push Button Event ID (PBE ID). This is a parameter that helps        to distinguish multiple push button events in the network. It        also helps to link PBENotification messages,        PBCActivated/PBCRequest messages, and PBCStart messages to a        specific push button event. The value of this parameter can be        taken, for instance, from Parameter A10 of the PBCRequest        message (PBE ID) (Parameter A14).

An alternative representation of the PBCStart message contains a list ofCDHN MAC Addresses of elected CDHN nodes (Parameter A12) or a list ofCDHN MAC Addresses of elected CDHN nodes with corresponding MACAddresses of the elected interfaces for the ts-PBC (Parameter A12 andA13) instead of just a single elected CDHN node or CDHN node andinterface.

A CDHN node that receives a PBCStart message may first check whether itis the elected CDHN node. This is the case if the CDHN MAC Address ofthe CDHN node is contained in Parameter A12 (CDHN MAC Address of electedCDHN node) of the received PBCStart message.

If this is the case, the elected CDHN node starts thetechnology-specific PBC run at the communication technology interfacespecified in Parameter A13 (MAC Address of the interface at which thets-PBC run has to be started) of the received PBCStart message. IfParameter A13 is not available, the ts-PBC run is started on allcommunication technology interfaces of the elected CDHN node.

The ts-PBC is already running at the enrollee, and now also thecorresponding ts-PBC at a CDHN node of the network is running. Due tothe election process at the CDHN registrar, the CDHN node is actually inreach of the enrollee and there is only a single CDHN node that runs thets-PBC for an interface of the enrollee. This prevents deadlocks causedby simultaneous ts-PBC runs.

The enrollee might have multiple communication interfaces of the sametechnology. Depending on the actual communication technology, this mightstill lead to deadlocks caused by simultaneous ts-PBC runs with thepreviously described method. Therefore, in an extension, the CDHNregistrar will elect no more than one CDHN node per communicationtechnology or communication technology which is prone to deadlocks ofthe ts-PBC (such as Wi-Fi Protected Setup). This restriction can bemade, for instance, by analyzing the Media information about thecommunication technology of the interface through which the PBCActivatedmessage has been received at the originator of the PBCRequest (ParameterA7 of the PBCRequest). In this extension, Media Information ofcommunication technology interface has to be included in the PBCRequest(Parameter A5 of the PBCActivated message or Parameter A7 of thePBCRequest message).

An alternative to sending the PBCActivated messages at level-1 by theenrollee as described above in the section on level-1 actions on E-PBEis the following:

-   -   On an enrollee Push Button Event E-PBE the enrollee starts the        technology-specific Push Button configuration methods (ts-PBC        methods), if available, on each of its unauthenticated (CDHN)        interfaces. There are no level-1 actions required except        starting the ts-PBC methods (the level-2 actions).    -   If the nodes of the CDHN are in state CDHN_PBC_enabled, they        wait for the receipt of technology-specific messages sent by the        enrollee announcing the wish for a ts-PBC.    -   If a CDHN node is in state CDHN_PBC_enabled and receives such        technology-specific messages from the enrollee, it performs        similar actions as if it had received a PBCActivated message        from the enrollee, for instance, duplicate detection,        construction of a PBCRequest message out of the        technology-specific PBC messages, and sending this PBCRequest        message to the CDHN registrar.

This alternative provides only technology-specific information about theenrollee to the CDHN node, but no CDHN specific information about theenrollee, especially not the CDHN MAC Address of the enrollee. Thisalternative will work fine, if the enrollee has only one interface whereit wants to perform a ts-PBC. The technology-specific information aboutthe enrollee is sufficient for the CDHN registrar to prevent overlappingPBC sessions and to avoid deadlock of ts-PBC runs in this case. However,if the enrollee has multiple interfaces where it wants to perform ats-PBC, the CDHN registrar will consider this as overlapping PBCsessions, because the CDHN MAC Address that is common to all theseinterfaces and connects all these interfaces to the same enrollee is notavailable to the CDHN registrar.

In order to illustrate the solution to the problems described for PushButton Configurations in Convergent Digital Home Networks to achieve areliable prevention of overlapping PBC sessions without any deadlocks oftechnology specific PBC methods, examples for using the two-level CDHNPush Button Configuration method (or two-step CDHN PBC approach) aregiven. The examples also make use of some of the extensions of thedescribed embodiment.

FIG. 4 shows an example network topology of a heterogeneous network suchas a Convergent Digital Home Network (CDHN). The network node devices D1. . . D6 of the Convergent Digital Home Network are connected with eachother through possibly heterogeneous communication technologies. Thenetwork node devices of the Convergent Digital Home Network are alsocalled CDHN nodes. Communication between devices of the network can beover multiple hops. The Convergent Digital Home Network of FIG. 4contains besides the network node devices respectively CDHN nodes D1 . .. D6 more network node devices than the cited ones and those devices areintermediate nodes on the communication between CDHN nodes D1 . . . D6.With respect to FIG. 2 the devices have different underlyingcommunication technologies MAC “A”, MAC “B”, MAC “C”, and MAC “E”. TheMAC “A” might be WLAN/WiFi (IEEE 802.11), the MAC “C” might be the PowerLine Communication (PLC; IEEE 1901), the MAC “E” might be Ethernet (IEEE802.3), and the MAC “B” might be some other communication technology,e.g. Multimedia over Coax Alliance (MoCA).

According to FIG. 4 the registrar functionality is assigned to thenetwork node device D6. It has been assigned the role of CDHN Registrarby some configuration mechanism, e.g. method M1. The information thatthe network node device D6 is the CDHN Registrar has been made availableto all CDHN nodes by some suitable means.

The nomenclature for the MAC addresses in the examples is as follows:

-   MAC_Dx CDHN MAC Address of CDHN device Dx-   MAC_Dx_X MAC Address of underlying communication technology MAC X at    CDHN device Dx. If there are multiple interfaces for communication    technology MAC X at the same CDHN device, they will be indexed    (MAC_Dx_Xi).

Note: Although there is some relationship between CDHN MAC address andinterface MAC address in the nomenclature of the MAC addresses, there isnone in the devices. Without any additional information, it cannot bederived from MAC_Dx and MAC_Dx_X that both addresses belong to the samedevice. The same applies to MAC_Dx_X and MAC_Dx_Y.

FIG. 6 shows based on FIG. 4 a modified topology of a Convergent DigitalHome Network (CDHN) with two enrollees—a new device ND1ND1 that a userwants to integrate into his Convergent Digital Home Network and an“accidential” new device ND2, whereas the registrar functionality isassigned to the network node device D6.

It is assumed in the cited CDHN topology that all network node devicesother than the network node devices D1 . . . D6 are consideredtransparent, so that the following neighbor relationships for thedescription is valid:

-   -   neighbors of D1 are D2, D3, and D6    -   neighbors of D2 are D1, D3, D4, D5, and D6    -   neighbors of D3 are D1, D2, and D6    -   neighbors of D4 are D2, D5, and D6    -   neighbors of D5 are D2, D4, and D6    -   neighbors of D6 are D1, D2, D3, D4, and D5

FIG. 7 shows based on the sequence diagram of FIG. 5 the flow ofmessages in the CDHN network shown in FIG. 6 in a sequence diagram. FIG.7 shows how according to the described embodiment overlapping PushButton Configuration (PBC) sessions are detected and how according tothe described embodiment authentication of multiple enrollees ND1 andND2 with the CDHN is prevented.

The user presses a push button at the network node device D3 of thenetwork node devices D1 . . . D6, which leads to a network Push ButtonEvent NW-PBE. Around the same time he presses a push button at the newdevice ND1, the enrollee, which leads to an enrollee Push Button EventE-PBE1. Somehow, a push button is also pressed at the “accidential” newdevice ND2, which leads to a enrollee Push Button Event E-PBE2.

Description of Events and Messages According to FIG. 7:

A network Push Button Event NW-PBE at the (first) network node devicerespectively CDHN node D3.

-   -   The CDHN node D3 goes into state CDHN_PBC_enabled for a CDHN        Walk Time of 120 seconds.    -   The CDHN node D3 broadcasts PBENotification message to its        neighbors the network node devices D1, D2, and D6. The        PBENotification message contains the following information: the        data “MAC_D3” as CDHN MAC Address of the originator of the        PBENotification message, the data “1913” as Push Button Event ID        (PBE ID).    -   The network node devices D1, D2, and D6 receive the        PBENotification message from the CDHN node D3 and go into state        CDHN_PBC_enabled for a CDHN Walk Time of 120 seconds.    -   The network node devices D1, D2, and D6 relay the        PBENotification message to their neighbors. The PBENotification        messages illustrated with thin lines are detected as duplicates        by the recipients and are not processed (discarded). The        duplicates are detected by comparing the CDHN MAC Address of the        originator of the PBENotification message (the data “MAC_D3”)        and the PBE ID (the data “1913”).    -   The CDHN nodes D4 and D5 receive the PBENotification message        from the CDHN node D2 and go into state CDHN_PBC_enabled for a        CDHN Walk Time of 120 seconds.    -   The CDHN nodes D4 and D5 relay the PBENotification message to        their neighbors.    -   An enrollee Push Button Event E-PBE1 at the new device        respectively the enrollee ND1. The user wants to include this        device in his home network. The enrollee ND1 goes into state        CDHN_PBC_enabled for a CDHN Walk Time of 120 seconds.        Furthermore, ND1 starts its technology-specific PBC run for MAC        A with a technology-specific walk time of 120 seconds.    -   The enrollee ND1 sends out PBCActivated messages on its        interface MAC_ND1_A (MAC “A”). The PBCActivated message contains        the following information: The data “MAC_ND1” as CDHN MAC        Address of the enrollee (Parameter A2), the data “2719” as PBE        ID (Parameter A3), the data “MAC_ND1_A” as MAC Address of the        interface through which the PBCActivated message is sent        (Parameter A4). Media information (Parameter A5) is not included        in this example.

The enrollee ND1 may send only one PBCActivated message on its interfaceMAC_ND1_A (MAC “A”) if it can be ensured that the corresponding CDHNnode will receive this single PBCActivated message. If there is somediscovery mechanism involved where the CDHN node will not necessarilyreceive every PBCActivated message, the enrollee ND1 should send outmultiple PBCActivated messages, e.g., periodically. These multiplePBCActivated messages are identical in the main parameters A2, A3, A4,and A5. FIG. 7 shows only the first PBCActivated message sent by anenrollee (ND1 or ND2). Subsequent PBCActivated messages sent by anenrollee (ND1 or ND2) are detected as duplicates by the recipients andare not processed (discarded). The duplicates are detected by comparingParameter A2 (the data “MAC_ND1”) and Parameter A3 (the data “2791”) ofthe messages or Parameter A4 (the data “MAC_ND1_A”) and Parameter A3(the data “2791”) of the messages.

-   -   The CDHN nodes D1 and D2 adjacent to the enrollee ND1 each        receive a PBCActivated message from the enrollee ND1.    -   CDHN node D1 sends a PBCRequest message to the CDHN registrar        D6. The PBCRequest message contains the following information:        The information received in the PBCActivated message (the data        “MAC_ND1”, “2791”, “MAC_ND1_A”), MAC “A” as Media information on        the receiving interface (Parameter A7), the information “medium”        as Link Quality (Parameter A8), the data “MAC_D1” as CDHN MAC        Address of the recipient of the PBCActivated message/originator        of the PBCRequest message (Parameter A9), the data “1913” as PBE        ID (Parameter A10), the data “MAC_D1_A” as MAC Address of the        interface through which the PBCActivated message has been        received (Parameter A11).    -   The CDHN registrar D6 receives the PBCRequest message from D1,        stores its information and waits for T_wait_PBCRequest for        further PBCRequest messages.    -   The CDHN node D2 sends a PBCRequest message to the CDHN        registrar D6. The PBCRequest message contains the following        information: The information received in the PBCActivated        message (the data “MAC_ND1”, “2791”, “MAC_ND1_A”), MAC “A” as        Media information on the receiving interface (Parameter A7), the        information “excellent” as Link Quality (Parameter A8), the data        “MAC_D2” as CDHN MAC Address of the recipient of the        PBCActivated message/originator of the PBCRequest message        (Parameter A9), the data “1913” as PBE ID (Parameter A10), the        data “MAC_D2_A” as MAC Address of the interface through which        the PBCActivated message has been received (Parameter A11).    -   The CDHN registrar D6 is waiting for further PBCRequest        messages. The CDHN registrar D6 receives the PBCRequest message        from the network node device D2 and stores its information and        continues to wait for further PBCRequest messages.    -   An “accidential” enrollee Push Button Event E-PBE2 at the new        device respectively enrollee ND2. The new device ND2 that        accidentally receives a Push Button Event. The enrollee ND2 goes        into state CDHN_PBC_enabled for a CDHN Walk Time of 120 seconds.        Furthermore, ND2 starts its technology-specific PBC run for MAC        “B” with a technology-specific walk time of 120 seconds.    -   The enrollee ND2 sends out PBCActivated messages on its        interface MAC_ND2_B (MAC “B”). The PBCActivated message contains        the following information: The data “MAC_ND2” as CDHN MAC        Address of the enrollee (Parameter A2), the data “9591” as PBE        ID (Parameter A3), the data “MAC_ND2_B” as MAC Address of the        interface through which the PBCActivated message is sent        (Parameter A4). Media information (Parameter A5) is not included        in this example.

The enrollee ND2 may send only one PBCActivated message on its interfaceMAC_ND2_B (MAC “B”) if it can be ensured that the corresponding CDHNnode will receive this single PBCActivated message. If there is somediscovery mechanism involved where the CDHN node will not necessarilyreceive every PBCActivated message, the enrollee ND2 should send outmultiple PBCActivated messages, e.g., periodically. These multiplePBCActivated messages are identical in the main parameters A2, A3, A4,and A5. FIG. 7 shows only the first PBCActivated message sent by anenrollee (ND1 or ND2). Subsequent PBCActivated messages sent by anenrollee (ND1 or ND2) are detected as duplicates by the recipients andare not processed (discarded). The duplicates are detected by comparingParameter A2 (the data “MAC_ND2”) and Parameter A3 (the data “9591”) ofthe messages or Parameter A4 (the data “MAC_ND2_B”) and Parameter A3(the data “9591”) of the messages.

-   -   The CDHN node D5 receives a PBCActivated message from the        “accidential” enrollee ND2.    -   The CDHN node D5 sends a PBCRequest message to the CDHN        registrar D6. The PBCRequest message contains the following        information: The information received in the PBCActivated        message (the data “MAC_ND2”, “9591”, “MAC_ND2_B”), MAC “B” as        Media information on the receiving interface (Parameter A7),        Link Quality (Parameter A8) is not given, the data “MAC_D5” as        CDHN MAC Address of the recipient of the PBCActivated        message/originator of the PBCRequest message (Parameter A9), the        data “1913” as PBE ID (Parameter A10), the data “MAC_D5_B” as        MAC Address of the interface through which the PBCActivated        message has been received (Parameter A11).    -   The CDHN registrar D6 is still waiting for further PBCRequest        messages. CDHN registrar D6 receives the PBCRequest message from        the network node device D5 and stores its information and        continues to wait for further PBCRequest messages.    -   T_wait_PBCRequest is now over.    -   The CDHN registrar D6 analyses the received PBCRequest messages        for overlapping PBC sessions by comparing Parameter A2. Table 2        shows the received PBCRequest messages and the relevant        information.

TABLE 2 Relevant content of received PBCRequest messages for detectionof overlapping PBC sessions MAC Address of interface Enrollee CDHN atenrollee through which MAC Address PBCActivated message has (ParameterA2) been sent (Parameter A4) MAC_ND1 MAC_ND1_A MAC_ND1 MAC_ND1_A MAC_ND2MAC_ND2_B

There are two distinct Enrollee CDHN MAC Addresses (Parameter A2): thedata “MAC_ND1” and the data “MAC_ND2”. Therefore, there is more than oneenrollee trying to get authenticated with the Convergent Digital HomeNetwork. This constitutes overlapping PBC sessions. This is indicated bythe star (¤) next to the timeline of the CDHN registrar D6 in FIG. 7.

-   -   The CDHN registrar D6 issues an indication of overlapping PBC        sessions to the user interface and to other devices D1 . . . D5        of the Convergent Digital Home Network.    -   The network node devices D1 . . . D6, ND1, and ND2 will leave        state CDHN_PBC_enabled after CDHN Walk Time is over. The new        devices ND1 and ND2 will finish their technology-specific PBC        run without success after the technology-specific walk time is        over since no CDHN node had started the corresponding ts-PBC.

FIG. 8 shows based on the sequence diagram of FIG. 5 the flow ofmessages in the CDHN network shown in FIG. 6 in a sequence diagram. FIG.8 shows how according to the described embodiment a deadlock between PBCruns of the same technology (e.g. MAC “A”) for the enrollee ND1 isprevented. The sequence diagram is based on the modified topology of aConvergent Digital Home Network (CDHN) shown in FIG. 6 but without the“accidential” new device ND2 and whereas the registrar functionality isassigned again to the network node device D6.

The user presses again a push button at the network node device D3 ofthe network node devices D1 . . . D6, which leads to a network PushButton Event NW-PBE. Around the same time he presses a push button atthe new device ND1, the enrollee, which leads to an enrollee Push ButtonEvent E-PBE1.

Description of Events and Messages According to FIG. 8:

The events and messages are the same as in the sequence chart of FIG. 7up to the “accidential” enrollee Push Button Event E-PBE2 at the newdevice respectively enrollee ND2 in the first example. In other wordsthe “accidential” enrollee Push Button Event E-PBE2 does not happen.

-   -   T_wait_PBCRequest is now over.    -   CDHN registrar D6 analyses the received PBCRequest messages for        overlapping PBC sessions by comparing Parameter A2. Table 3        shows the received PBCRequest messages and the relevant        information.

TABLE 3 Relevant content of received PBCRequest messages for detectionof overlapping PBC sessions MAC Address of interface Enrollee CDHN atenrollee through which MAC Address PBCActivated message has (ParameterA2) been sent (Parameter A4) MAC_ND1 MAC_ND1_A MAC_ND1 MAC_ND1_A

There is only one distinct Enrollee CDHN MAC Address (Parameter A2): Thedata “MAC_ND1”. Therefore, there is only one enrollee trying to getauthenticated with the CDHN. This constitutes a non-overlapping PBCsession.

-   -   The CDHN registrar D6 elects a CDHN node from the network nodes        D1, D2 of the CDHN nodes D1 . . . D6 of the CDHN network for        running the technology-specific PBC (ts-PBC). The CDHN registrar        D6 analyses the received PBCRequest messages for potential        deadlock of ts-PBC sessions by comparing Parameter A4 and A11 of        the received PBCRequest messages. Table 4 shows the received        PBCRequest messages and the relevant information for the        election of a CDHN node.

TABLE 4 Relevant content of received PBCRequest messages for election ofCDHN node MAC Address of MAC Address of CDHN MAC Address interface atenrollee the interface at the of CDHN node Media Enrollee through whichCDHN node through (recipient PBCActivated information on CDHN MACPBCActivated mes- which the PBCActivated message/originator receivingLink Address sage has been sent message has been received PBCRequestmessage) interface Quality (Parameter A2) (Parameter A4) (Parameter A11)(Parameter A9) (Parameter A7) (Parameter A8) MAC_ND1 MAC_ND1_A MAC_D1_AMAC_D1 MAC A Medium MAC_ND1 MAC_ND1_A MAC_D2_A MAC_D2 MAC A Excellent

There is only one distinct Parameter A4 (the data “MAC_ND1_A”). For theParameter A4=MAC_ND1_A, there are two distinct Parameter A11 (the data“MAC_D1_A” and the data “MAC_D2_A”) indicating two candidate CDHN nodesfor the ts-PBC (MAC_D1 and MAC_D2). Starting the ts-PBC at both thenetwork node device D1 and the network node device D2 has the potentialfor a deadlock of ts-PBC sessions, especially if additional knowledgederived from the media information (MAC “A”) indicates this.

-   -   The CDHN registrar D6 elects the network node device D2 as CDHN        node for the ts-PBC since Parameter A8 indicates that the        PBCRequest with Parameter A11=MAC_D2_A is the better choice        (Link Quality is excellent, compared to medium for Parameter        A11=MAC_D1_A).    -   The CDHN registrar D6 sends a PBCStart message to the elected        CDHN node D2. The PBCStart message contains the following        information: The data “MAC_D2” as CDHN MAC Address of the        elected network node (Parameter A12), the data “MAC_D2_A” as MAC        Address of the interface for the ts-PBC (Parameter A13), the        data “1913” as PBE ID (Parameter A14)    -   The elected CDHN node D2 receives the PBCStart message, does        some sanity check (CDHN MAC Address of the CDHN node D2 is value        of Parameter A12, PBE ID is current, etc.) which passes        successfully.    -   The CDHN node D2 starts its technology-specific PBC run for MAC        “A” at the interface with MAC Address “MAC_D2_A” with a        technology-specific walk time of 120 seconds.    -   Since the enrollee ND1 has already its technology-specific PBC        running and the CDHN node D2 starts its ts-PBC within the        technology-specific walk time at ND1, the ts-PBC finds a match        and finishes with success.    -   The technology-specific walk times at the enrollee ND1 and the        CDHN node D2 are finished with the successful ts-PBC session.    -   The network node devices D1 . . . D6 and ND1 will leave state        CDHN_PBC_enabled after CDHN Walk Time is over.

With the election of the CDHN node D2 for the technology-specific PBC,the deadlock of the ts-PBC session at the CDHN node D1 and the CDHN nodeD2 has been prevented. Furthermore, the election based on the linkquality allows choosing the better link for the communication technologyMAC “A”.

FIG. 9 shows the structure of the network node devices D1, D2, D4; D1 .. . D5, especially the registrar network node device D2; D6, each withat least one interface for controlling the run of technology specificPush Button Configuration sessions within a heterogeneous network withmultiple communication network technologies based on the abstractionlayer embedded in the IEEE P1905.1-Architecture above the Media AccessControl (MAC)-layer and the Physical layer according to FIG. 2.According to FIG. 9 the network node devices D1, D2, D4; D1 . . . D5,especially the registrar network node device D2; D6, in contrast to thenetwork node device NND of FIG. 2, include the capability of performinga Push Button Event (PBE) M1, controlling the run of technology specificPush Button Configuration sessions M2 and sending/receiving informationand/or messages M3. While M3 includes or incorporates all entities ofthe IEEE P1905.1-Architecture belonging to the Physical Layer and M1incorporates the entities of the IEEE P1905.1-Architecture belonging tothe Application Layer entities, which are part of the Higher LayerEntities (HLE), controlling the run of technology specific Push ButtonConfiguration sessions M2 incorporates all entities in the data- andmanagement plane of the IEEE P1905.1-Architecture from the MAC-Layerincluding the Abstraction Layer with the IEEE P1905.1 AbstractionManagement Entity (ALME) and the corresponding Service Access Points(SAP) via the Logical Link Control (LLC) up to the Higher Layers withits most entities.

A description has been provided with particular reference to preferredembodiments thereof and examples, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the claims which may include the phrase “at least one of A, B and C”as an alternative expression that means one or more of A, B and C may beused, contrary to the holding in Superguide v. DIRECTV, 358 F3d 870, 69USPQ2d 1865 (Fed. Cir. 2004).

The invention claimed is:
 1. A method for controlling a run oftechnology specific Push Button Configuration sessions within aheterogeneous network with multiple communication network technologiesand a plurality of network node devices interconnected to each other viaat least one interface and/or over multiple hops and authenticated orunauthenticated for the network, comprising: enabling a two-level PushButton Configuration within the heterogeneous network, within aConvergent Digital Home Network according to IEEE P1905.1, by aregistrar network node device that is one of selected and predeterminedfrom among authenticated network node devices that are authenticated forthe network, by performing in level-1 of the two-level Push ButtonConfiguration: triggering a first network node device among theauthenticated network node devices, by a first Push Button Event that isone of virtual and physical and is assigned to the first network nodedevice, to send via the at least one interface a notification messageabout the first Push Button Event directly or indirectly to theregistrar network node device and at least one other authenticatednetwork node device; triggering, as an enrollee, at least one secondnetwork node device, among the network node devices, eachunauthenticated for the network, by at least one second Push ButtonEvent that is one of virtual and physical, respectively assigned to theat least one second network node device, to start a technology specificPush Button Configuration at the at least one second network node deviceand to notify, via the at least one interface, at least one adjacentnetwork node device, among the authenticated network node devices,adjacent to the at least one second network node device using at leastone technology specific message announcing at least one of a request fora technology specific Push Button Configuration session and a PBCactivated message; forwarding to the registrar network node device, viathe at least one interface by the at least one adjacent network nodedevice that received the at least one technology specific message, a PBCrequest message based on the at least one technology specific message,directly or indirectly via at least one third network node device amongthe authenticated network node devices that is not adjacent to the atleast one second network node device; counting the at least one secondnetwork node devices at the registrar network node based on devicespecific data received with each PBC request message; sending, via theat least one interface when only one second network node device iscounted, a PBC start message only to a single elected network nodedevice among the authenticated network node devices that received thenotification message; and establishing, by the elected network nodedevice, the technology specific Push Button Configuration session withthe second network node device; and running the technology specific PushButton Configuration session in a level-2 of the two-level Push ButtonConfiguration by the elected network node device and the second networknode device.
 2. The method according to claim 1, wherein the PBCactivated message contains a MAC address of the enrollee.
 3. The methodaccording to claim 1, wherein the PBC activated message contains atleast one of a Push Button Event Identifier, a MAC address of aninterface through which the PBC activated message is sent and mediainformation about the communication technology of the interface throughwhich the PBC activated message is sent.
 4. The method according toclaim 1, wherein the PBC request message contains a MAC address of atleast one of a recipient of the technology specific message and anoriginator of the PBC request message.
 5. The method according to claim4, wherein the PBC request message contains at least one of a PushButton Event Identifier for linking at least one of the notificationmessage, the PBC activated message and the PBC request message to aspecific Push Button Event; information about the link quality; a MACaddress of an interface through which the at least one technologyspecific message is received; and media information about communicationtechnology of the interface through which the at least one technologyspecific message is received.
 6. The method according to claim 1,wherein the device specific data include at least one of a MAC addressof a first interface through which the PBC activated message is sent,and the MAC address of a second interface through which the at least onetechnology specific message is received.
 7. The method according toclaim 1, wherein the registrar network node device elects the electednetwork node device when all received PBC request messages containidentical device specific data; when all received PBC request messagescontain an identical MAC address of a first interface through which thePBC activated message is sent; and when communication technologyinterfaces are potential PBC partners for a same interface of theenrollee based on received PBC request messages for a distinct MACaddress of the first interface through which the PBC activated messageis sent containing at least two of a first MAC address of at least oneof a recipient of the at least one technology specific message and anoriginator of the PBC request message, information about the linkquality, a second MAC address of a second interface through which the atleast one technology specific message is received, and media informationabout communication technology of the second interface through which theat least one technology specific message is received.
 8. The methodaccording to claim 1, wherein the PBC start message contains a MACaddress of the elected network node device which is at least one of arecipient of the at least one technology specific message and anoriginator of the PBC request message.
 9. The method according to claim8, wherein the PBC start message contains at least one of a Push ButtonEvent Identifier linking at least one of the notification message, thePBC activated message and the PBC request message and the PBC startmessage to a specific Push Button Event; and a MAC address of aninterface at which a technology specific PBC run is started.
 10. Aregistrar network node device with at least one interface forcontrolling a run of technology specific Push Button Configurationsessions within a heterogeneous network with multiple communicationnetwork technologies with a plurality of other network node devicesinterconnected to each other via at least one interface and/or overmultiple hops and authenticated or unauthenticated for the network,being authenticated for the network and especially selectable ordetermined, comprising: a processor coupled to a memory; a PBE enginefor performing a Push Button Event; a communication interface forsending/receiving at least one of information and messages enabling atwo-level Push Button Configuration within a Convergent Digital HomeNetwork according to IEEE P1905.1, in level-1 of the two-level PushButton Configuration triggered by the PBE engine to send via the atleast one interface a notification message about a first Push ButtonEvent that is one of virtual and physical, directly or indirectly to atleast one second network node device among the other network nodedevices that are authenticated, and receive, via the at least oneinterface directly or indirectly via at least one of the other networknode devices, from at least one of the at least one second network nodedevice, at least one PBC request message based on at least onetechnology specific message announcing at least one of a request for atechnology specific Push Button Configuration session and a PBCactivated message generated by at least one third network node device,among the other network node devices that are unauthenticated, as anenrollee in a technology specific Push Button Configuration based on asecond Push Button Event that is virtual or physical and is assigned tothe at least one third network node device and sent by the at least onethird network node device via the at least one interface to at least oneadjacent network node device adjacent to the at least one third networknode device; and a controller for controlling the run of technologyspecific Push Button Configuration sessions by counting the at least onethird network node device based on device specific data received witheach PBC request message, and sending, when applicable based on thecounting, via the communication interface and the at least oneinterface, a PBC start message only to a single elected network nodedevice among the authenticated network node devices that received thenotification message, to establish the technology specific Push ButtonConfiguration session by the elected network node device and the thirdnetwork node device in level-2 of the two-level Push ButtonConfiguration.
 11. A registrar network node device with at least oneinterface for controlling a run of technology specific Push ButtonConfiguration sessions within a heterogeneous network with multiplecommunication network technologies with a plurality of other networknode devices interconnected to each other via at least one interfaceand/or over multiple hops and authenticated or unauthenticated for thenetwork, being authenticated for the network and especially selectableor determined, comprising: a processor coupled to a memory; acommunication interface for sending/receiving at least one ofinformation and messages enabling a two-level Push Button Configurationwithin a Convergent Digital Home Network according to IEEE P1905.1, inlevel-1 of the two-level Push Button Configuration to receive anotification message triggered by a first Push Button Event that is oneof virtual and physical and is assigned to a first network node deviceamong the other network node devices that are authenticated, send viathe at least one interface the notification message about the first PushButton Event, directly or indirectly to at least one second network nodedevice among the other network node devices that are authenticated, andreceive, via the at least one interface directly or indirectly via atleast one of the other network node devices, from at least one of the atleast one second network node device, at least one PBC request messagebased on at least one technology specific message announcing at leastone of a request for a technology specific Push Button Configurationsession and a PBC activated message generated by at least one thirdnetwork node device, among the other network node devices that areunauthenticated, as an enrollee in a technology specific Push ButtonConfiguration based on a second Push Button Event that is virtual orphysical and is assigned to the at least one third network node deviceand sent by the at least one third network node device via the at leastone interface to at least one adjacent network node device adjacent tothe at least one third network node device; and a controller forcontrolling the run of technology specific Push Button Configurationsessions by counting the at least one third network node device based ondevice specific data received with each PBC request message, andsending, when applicable based on the counting, via the communicationinterface and the at least one interface, a PBC start message only to asingle elected network node device among the authenticated network nodedevices that received the notification message, to establish thetechnology specific Push Button Configuration session by the electednetwork node device and the third network node device in level-2 of thetwo-level Push Button Configuration.
 12. The registrar network nodedevice according to claim 11, wherein the PBC activated message containsa MAC address of the enrollee.
 13. The registrar network node deviceaccording to claim 11, wherein the PBC activated message contains atleast one of a Push Button Event Identifier, a MAC address of aninterface through which the PBC activated message is sent and mediainformation about the communication technology of the interface throughwhich the PBC activated message is sent.
 14. The registrar network nodedevice according to claim 11, wherein the PBC request message contains aMAC address of at least one of a recipient of the technology specificmessage and an originator of the PBC request message.
 15. The registrarnetwork node device according to claim 14, wherein the PBC requestmessage contains at least one of a Push Button Event Identifier forlinking at least one of the notification message, the PBC activatedmessage and the PBC request message to a specific Push Button Event;information about the link quality; a MAC address of an interfacethrough which the at least one technology specific message is received;and media information about communication technology of the interfacethrough which the at least one technology specific message is received.16. The registrar network node device according to claim 11, wherein thedevice specific data include at least one of a MAC address of a firstinterface through which the PBC activated message is sent, and the MACaddress of a second interface through which the at least one technologyspecific message is received.
 17. The registrar network node deviceaccording to claim 11, wherein the registrar network node device electsthe elected network node device when all received PBC request messagescontain identical device specific data; when all received PBC requestmessages contain an identical MAC address of a first interface throughwhich the PBC activated message is sent; and when communicationtechnology interfaces are potential PBC partners for a same interface ofthe enrollee based on received PBC request messages for a distinct MACaddress of the first interface through which the PBC activated messageis sent containing at least two of a first MAC address of at least oneof a recipient of the at least one technology specific message and anoriginator of the PBC request message, information about the linkquality, a second MAC address of a second interface through which the atleast one technology specific message is received, and media informationabout communication technology of the second interface through which theat least one technology specific message is received.
 18. The registrarnetwork node device according to claim 11, wherein the PBC start messagecontains a MAC address of the elected network node device which is atleast one of a recipient of the at least one technology specific messageand an originator of the PBC request message.
 19. The registrar networknode device according to claim 18, wherein the PBC start messagecontains at least one of a Push Button Event Identifier linking at leastone of the notification message, the PBC activated message and the PBCrequest message and the PBC start message to a specific Push ButtonEvent; and a MAC address of an interface at which a technology specificPBC run is started.
 20. At least one non-transitory computer readablestorage medium embodying computer instructions, executable by at leastone processor in at least one network node device, for controlling a runof technology specific Push Button Configuration sessions within aheterogeneous network with multiple communication network technologieswith a plurality of network node devices interconnected to each othervia at least one interface and/or over multiple hops and authenticatedor unauthenticated for the network, comprising: enabling a two-levelPush Button Configuration within the heterogeneous network, within aConvergent Digital Home Network according to IEEE P1905.1, by aregistrar network node device that is one of selected and predeterminedfrom among authenticated network node devices that are authenticated forthe network, by performing in level-1 of the two-level Push ButtonConfiguration: triggering a first network node device among theauthenticated network node devices, by a first Push Button Event that isone of virtual and physical and is assigned to the first network nodedevice, to send via the at least one interface a notification messageabout the first Push Button Event directly or indirectly to theregistrar network node device and at least one other authenticatednetwork node device; triggering, as an enrollee, at least one secondnetwork node device, among the network node devices, eachunauthenticated for the network, by at least one second Push ButtonEvent that is one of virtual and physical, respectively assigned to theat least one second network node device, to start a technology specificPush Button Configuration at the at least one second network node deviceand to notify, via the at least one interface, at least one adjacentnetwork node device, among the authenticated network node devices,adjacent to the at least one second network node device using at leastone technology specific message announcing at least one of a request fora technology specific Push Button Configuration session and a PBCactivated message; forwarding to the registrar network node device, viathe at least one interface by the at least one adjacent network nodedevice that received the at least one technology specific message, a PBCrequest message based on the at least one technology specific message,directly or indirectly via at least one third network node device amongthe authenticated network node devices that is not adjacent to the atleast one second network node device; counting the at least one secondnetwork node devices at the registrar network node based on devicespecific data received with each PBC request message; sending, via theat least one interface when only one second network node device iscounted, a PBC start message only to a single elected network nodedevice among the at least one adjacent network node device; andestablishing, by the elected network node device, the technologyspecific Push Button Configuration session with the second network nodedevice; and running the technology specific Push Button Configurationsession in a level-2 of the two-level Push Button Configuration by theelected network node device and the second network node device.
 21. Aheterogeneous network for controlling a run of technology specific PushButton Configuration sessions, comprising: a processor coupled to amemory; a plurality of network node devices interconnected to each othervia at least one interface and/or over multiple hops and authenticatedor unauthenticated for the heterogeneous network, including a firstnetwork node device that is authenticated and generates a notificationmessage triggered by a first Push Button Event that is one of virtualand physical and is assigned to the first network node device, at leastone second network node device, each unauthenticated for theheterogeneous network, starting a technology specific Push ButtonConfiguration triggered by at least one second Push Button Event that isone of virtual and physical, respectively assigned to the at least onesecond network node device, and sending, via the at least one interface,at least one technology specific message announcing at least one of arequest for a technology specific Push Button Configuration session anda PBC activated message, at least one adjacent network node deviceadjacent to and receiving from each of the at least one second networknode device, the at least one technology specific message and sending atleast one PBC request message based on the at least one technologyspecific message; and a registrar network node device, including acommunication interface for sending/receiving at least one ofinformation and messages enabling a two-level Push Button Configurationwithin a Convergent Digital Home Network according to IEEE P1905.1, inlevel-1 of the two-level Push Button Configuration to receive thenotification message from first network node device via the at least oneinterface and forward the notification message about the first PushButton Event, directly or indirectly, to other of the network nodedevices that are authenticated, and receive, via the at least oneinterface directly or indirectly via at least one of the network nodedevices, from at least one of the adjacent network node devices, the atleast one PBC request message; and a controller for controlling the runof technology specific Push Button Configuration sessions by countingthe at least one second network node device based on device specificdata received with each PBC request message, and sending, whenapplicable based on the counting, via the communication interface andthe at least one interface, a PBC start message only to a single electednetwork node device among authenticated network node devices thatreceived the notification message, to establish the technology specificPush Button Configuration session by the elected network node device andthe second network node device in level-2 of the two-level Push ButtonConfiguration.